McFeeley said the freedom they received from the studio allowed for "some really good storytelling".

"There wasn't a mandate that everything has to get tied up in a neat bow so that we can continue with another [movie] and another one and another one [or] 'these characters are sacred and can't move too far'," he said.

"I feel these movies are at their most successful when the characters undergo big changes and, in our case, when some are escorted off the stage."

Chris Hemsworth’s Thor is back with an eye patch after losing his right eye in Thor: Ragnarok. Picture: Film Frame/Marvel Studios

That kind of language doesn't bode well for our heroes, and suggests that Chris Hemsworth's Thor, Chris Evans' Captain America and Robert Downey Jnr's Iron Man could be on the chopping block. (We also know that each of these stars' contracts with Marvel are up.)

But don't reach for the tissues just yet. While the writers strongly hinted the superheroes' lives were in jeopardy, it's not clear whether anyone will be killed off in Infinity War or the fourth Avengers movie, which isn't due for release until May 2019.

Because two movies were shot back-to-back in Atlanta throughout much of 2016, the filmmakers and stars often speak about them as if they are one project.

Will Robert Downey Jnr’s Iron Man make it out alive? Picture: Marvel Studios

That said, the writers promise that each film stands on its own. McFeeley goes so far as to suggest "they'll nearly feel like two different genres".

The filmmakers and stars are sworn to secrecy about exactly what will go down in Infinity War, but the writers say the villain, Thanos, is so central to the story that he acts as the main character.

The bad guy is on the hunt for the hallowed Infinity Stones - and the consequences for the universe will be dire if he manages to get his hands on all of them.

The big bad … Thanos, played by Josh Brolin, will challenge the Avengers like never before. Picture: Film Frame/Marvel Studios

It hasn't always been happy families between the type-A personalities that make up the Avengers, but Downey Jnr suggests the characters will be forced to work together to take on the new villain, who is "the sum of all our fears".

"Because the threat has risen to a new level, which is really saying something, whether we want to band together or not, we won't survive unless we do," he said.

Spider-Man (Tom Holland) will find his place among the band of superheroes in Infinity War. Picture: Chuck Zlotnick/Marvel Studios

For Iron Man, Captain America, Thor and the gang, the stakes could not be higher.

"Very often in comic book movies, we sort of just write 'and the fate of the world is at stake'," McFeeley said.

"Thanos, to honour him as a character, the fate of the world really is at stake because he has high-minded goals about how the universe ought to be run.

"He thinks the universe should look one particular way. He wants to fix the universe as he sees it."

While viewers are dying to know exactly what will happen, directors Anthony and Joe Russo have worked hard to keep the movies a surprise for the fans: "There's a lot of very risible things that happen in these films and we wanted to keep them very quiet and private and secret because we want your experience of going to the movie to be the moment where you discover those things."

Thankfully, Aussies won't have to wait much longer to get answers. Avengers: Infinity War is out on Wednesday, April 25.

The journalist travelled to Atlanta courtesy of Disney, which owns Marvel Studios.